Either the content of instruction, the vehicle of instruction, or the period of instruction.
- The ideas (content of instruction) the ego tries to teach us, called “dark lessons” (see T-14.XI.4-5). The central lesson in these is that God’s Son is guilty.
- The ideas the Holy Spirit tries to teach us as a correction for the ego’s lessons. His single lesson—the essence of all His lessons—is forgiveness, or the idea that God’s Son is guiltless.
- The situations in our lives (vehicle of instruction), which the Holy Spirit uses to teach us His lesson that nothing outside us can hurt us, disturb our peace, or diminish our love (see T-31.VIII.3:1).
- In the Workbook, the idea for the day is sometimes called the lesson, for it is the content we are supposed to learn that day.
- The whole Workbook lesson is sometimes called the lesson, for it is the vehicle for that day’s learning.
- A practice period is at times called a lesson, for it is the period in which we learn. (“These practice sessions, like our last review, are centered round a central theme with which we start and end each lesson [each practice session]”—W‑pI.rVI.In.3:1.)